1. Field of the Invention
The present invention relates to a surgical stapling and cutting instrument adapted for use in the diagnosis and therapy of pathologies treated by stapled resection. More particularly, the invention relates to a retaining pin lever employed in the advancement mechanism of a surgical stapling and cutting instrument.
2. Description of the Prior Art
Within the field of surgery the need to surgically seal tissue and to cut tissue is quite commonplace. Sealing of tissue may be accomplished by numerous sealing devices, such as, surgical staplers. Cutting of tissue may be accomplished by numerous cutting devices, such as, scalpels or surgical scissors. Stapling and cutting of tissue in several steps during a surgical procedure adds time and potential complications to the procedure. In order to reduce the procedural steps and the time needed for performing various surgical procedures, surgical stapling and cutting instruments have been developed which simultaneously perform the steps of stapling and cutting tissue. As those skilled in the art can certainly appreciate, it is desirable that such surgical stapling and cutting instruments allow for multiple cutting and stapling actions during a single procedure.
Many current surgical stapling and cutting instruments provide stapling and cutting mechanisms that operate in the same direction during device actuation, or firing; that is, linear surgical stapling devices. For instance, the staple formation and the tissue cutting occur through the same plane on the tissue. These devices generally utilize an anvil, which holds staple pockets (or staple forming surfaces) and a washer, and a cartridge housing, which holds staples and a knife. The anvil is generally a permanent element of the device and the cartridge housing is either a permanent element (single-fire) or a reloadable element (multiple-fire).
Tissue is captured between the anvil and the cartridge housing of the device. A device called a retaining pin runs between the cartridge housing and the anvil. The purpose of the retaining pin is two fold. First, the retaining pin helps align the cartridge housing with the anvil to ensure the staples in the cartridge housing line up with the anvil pockets in the anvil so good staples are formed upon actuation of the surgical stapling and cutting instrument. Second, the retaining pin acts as a wall to capture the tissue between the anvil and the cartridge housing. Clamping of the device moves the cartridge housing to a set distance from the anvil to apply pressure to the tissue.
During camping and releasing, certain surgical devices use mechanisms to automatically advance the retaining pin to capture the tissue. Activation of the device moves the staples from the cartridge housing toward the anvil. The staples puncture the captured tissue and then contact anvil pockets on the anvil, which form the staples into desired shapes to provide a seal.
In conjunction with the staple formation, actuation of the device also moves the knife from the cartridge housing toward the anvil. The knife pushes the tissue toward the anvil and, upon contact of the knife with the washer on the anvil, cutting of the tissue is facilitated. This cutting is similar to that which is performed on a cutting board.
The advancement of the retaining pin is important to surgeons and to the procedure, thus some desire to manually advance the retaining pin prior to closure of the instrument as it make it easier to locate the instrument on the specific tissue to be retained and then cut and sealed. Others, however, prefer to have the retaining pin advance automatically with operation of the instrument and don't want to be bothered with manually advancement and retraction. In staplers that perform both of these functions, automatic advancement as well as allow manual advancement, the retaining pin of will automatically retract should the surgeon reopen the stapler in order to reposition the stapler. This may allow the tissue to move out of the stapler and cause the surgeon to delay the procedure while the tissue is repositioned and the retaining pin is once again advanced into the anvil.
As such, a need exists for a improved retaining pin advancement mechanism. The present invention provides such an improvement whereby a surgeon can control the retaining pin actuation mechanism. The retaining pin actuation mechanism including a lever rotationally connected to the handle for facilitating both manual and automatic advancement of the retaining pin and requiring manual retraction of the retaining pin.